The term "craving" has been used to describe drug users" desires, wants, or needs for a drug. Users report that severe drug craving is partially responsible for continued drug use, as well as relapse to drug taking after a drug-free period. Despite the potential importance of craving in continued drug use, there have been few experimental studies designed to measure craving. Part of the difficulty in studying craving is that the term is imprecise and subject to a number of interpretations. In addition, it does not necessarily vary in a predictable way with drug use. There are at least three distinct conditions under which craving reportedly occurs: 1) during abstinence, in the absence of internal (drug-induced) or external (environmental) cues associated with drug use (Craving/no cues), 2) in the presence of environmental cues associated with drug use (Craving/with external cues), and 3) in the presence of internal cues associated with drug use (Craving/with internal cues). The proposed study will evaluate craving by laboratory animals who will live in a three- chambered residence; cues related to smoked cocaine self-administration will be specific to one chamber, cues related to food pellet self- administration will be specific to a second chamber, and cues related to neither cocaine nor food pellets will be present in a third middle chamber that separates the other two chambers. The primary purpose of the study is to compare the acquisition of craving for smoked cocaine in the presence (Craving/with external cues: i.e., responding in the presence of an illuminated lever light without session lights) or absence (Craving/no cues: i.e., the amount of time spent in a chamber out-of-session) of cues. Craving in the presence of internal cues will not be evaluated in this proposal due to time limitations. Smoked cocaine will be evaluated in the present study because it is a potent reinforcer, and we expect that it will induce robust craving, as operationally defined above. Smoked lidocaine, which produces local anesthesia like cocaine, but has little or no reinforcing effects, will be tested as a control drug.